Rabbits are being injected intravenously with oxidized papain at 2 to 4 day intervals, with or without administration of other compounds expected to increase or decrease the effect of the papain. Light and electron microscopic evaluation of the livers and other organs of the rabbits is then performed on sequential liver biopsies and finally tissues obtained at necropsy. The major purpose of this study is to develop a model for testing potential therapeutic/prophylactic agents in individuals who are alpha 1-antitrypsin deficient, while at the same time evaluating hypotheses regarding the pathogenesis of the liver damage these patients have.